What Is an SOA Record?

What Is an SOA Record?

An SOA (Start of Authority) record is a vital component of DNS records, facilitating seamless domain data exchange between DNS servers. This record encapsulates crucial domain details such as the primary name server, the domain owner’s contact information, and the specifics of data caching. In this comprehensive guide, we’re going to demystify the components of an SOA record, using gcore.com as our case study.

Key Characteristics of an SOA Record

An SOA record is not merely a static element, but a dynamic cornerstone of your DNS infrastructure. It automatically updates whenever there are changes made to your domain’s zone (the network of DNS records). Moreover, an SOA record is inherently tied to the domain zone and only disappears when the zone is deleted. It’s important to note that any zone without an SOA record is non-compliant with the RFC 1035 (5.2) standards and thus, is not suitable for IP nodes.

In a nutshell, SOA records are:

  1. Created and updated automatically
  2. Automatically deleted and cannot be manually removed
  3. Essential for the proper functioning of the domain

Exploring the Elements of an SOA Record

To understand the constituents of an SOA record better, let’s inspect our website’s domain gcore.com. We’ve examined its SOA record using the Google Admin Toolbox.

The SOA record for gcore.com

Here are the parameters:

  • MNAME:  This signifies the primary DNS server for the zone. For gcore.com, it is ns1.gcorelabs.net
  • RNAME: This contains the contact email address, where the ‘@’ is replaced with a dot. For gcore.com, it’s support@gcore.com
  • Serial: This unique 32-bit identifier keeps track of zone changes. For gcore.com, it’s 1685523010
  • Refresh: This advises secondary DNS servers about the frequency of checks to the primary DNS server, set at every 1 h 30 min for gcore.com
  • Retry: This indicates the waiting period before a secondary DNS server retries a failed check to the primary DNS server. For gcore.com, it is 1 h
  • Expire: This specifies the duration after which a secondary DNS server should cease providing domain information if it cannot connect to the primary DNS server. For gcore.com, this is set at 14 days
  • TTL: This indicates how long other servers should retain information about this domain in their cache. For gcore.com, this duration is 5 min

The “Data” line succinctly summarizes the above information, with time durations expressed in seconds.


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